Internal combustion percussive hammer



July 26, 1938., c. L. CHARLES 2,125,013

INTERNAL' COMBUSTION PERCUSSIVE HAMMER Filed May 3, 1957 5 Sheets-Sheet 1 l'illlli ml 23* v jrzaew" 6227"; j Czar/e6;

July 26, 1938. C, CH RLE 2,125,013

INTERNAL COMBUSTION PERCUSSIVE HAMMER July 26, 1938. c. L. CHARLES 2,125,013

INTERNAL COMBUSTION PERCUSSIVE HAMMER Filed May 3, 1957 3 Sheets-Sheet 5 1% 667% CCZTZI U/(Qrieg qja Patented July 26, 1938 UNITED STATES PATENT OFFICE Carl L. Charles, Winnetka, Ill., assignor to Gas Tool Patents Corporation,

Delaware a corporation of Application May 3, 1937, Serial No. 140,504

22 Claims.

This invention relates to an internal combustion percussive hammer, and more particularly to improved means for subduing the reciprocation of the piston when the hammer is not working and for rotating the tool during drilling.

One feature of this invention is that it provides means for automatically subduing the reciprocation of the piston when the hammer is lifted, either by lessening the frequency of such reciprocation or by stopping it completely; another feature of this invention is that it automatically eliminates the destructive vibration present when such a hammer is lifted from working position; yet another feature is that improved throttle means is provided so constructed and arranged that it enables variation of the amount of combustible charge entering the cylinder and at the same time withstands the vibration of such a hammer; a further feature is that improved means for stopping and starting the hammer, without shifting the hands from working position, is provided; another feature is that simple and effective tool rotation is provided during drilling; other features and advantages of this invention will be apparent from the following specification and the drawings, in which:

Figure 1 is an elevation, partly in section, of a hammer embodying this invention; Fig. 2 is a top plan view of the hammer shown in Fig. 1; Fig. 3 is a vertical sectional view of the hammer shown in Fig. 1, transverse to that view; Fig. 4 is a horizontal sectional View of the ratchet de- Vice, along the line 4-4 of Fig. 3; Fig. 5 is a fragmentary detail view showing the range of movement of the throttle member; Fig. 6 is a top plan View of a hammer embodying a modified handle control arrangement; and Fig. '7 is a partial vertical section along the line 'l--'l of Fig. 6.

Internal combustion percussive hammers, particularly of the free piston type wherein the piston return is by a spring, have many problems and difficulties peculiar to themselves. One problem is that of subduing the reciprocation of the piston when the hammer is lifted from working position and held in the air by the operator, as

when he desires to move from one place to another in order to start the tool working in another spot. When the hammer is lifted the entire force of the downward movement and impact of the piston, as a result of explosion of the combustible charge thereabove, must be absorbed within the body and frame of the hammer itself. Where the hammer has a desired power when in working position, this force is frequently destructive in effect when the hammer is lifted, even though various means are used to cushion to some extent the impact. The average workman or operator, however, will not throw the ignition switch to stop the hammer before he lifts it, since in the type of hammer heretofore used this would involve subsequently removing the hands from working position on the handles, leaning the hammer against his thighs, and operating a starting rod to restart the working reciprocations of the piston.

The present invention obviates this objection in prior hammers of this type by providing means for automatically subduing the reciprocation of the piston when the hammer is lifted, and automatically restoring it to full force when the hammer is returned to working position, the operator leaving his hands in working position on the handles during movement of the hammer from place to place and not performing any conscious act to achieve the desired result. Two ways of accomplishing this result are disclosed herewith: in the first the intake passage is throttled to reduce the amount of combustible charge supplied to the cylinder, and thus the power and rapidity of the piston reciprocation; andin the second the piston is instantaneously stopped upon lifting of the hammer, and automatically restarted as soon as the hammer is replaced in a working position.

In the particular embodiment of this invention illustrated herewith in Figs. 1 to 5, an internal combustion percussive hammer is shown comprising a vertical cylinder I0 having a piston ll freely reciprocable therein. The piston operates in accordance with conventional two-cycle internal combustion practice, being driven downwardly by the explosion of a combustible charge thereabove and being returned by the spring assembly comprising the piston spring I2 and a cushion spring I3. A striker portion on the piston is adapted to meet an anvil I4 at the end of each downward movement, transmitting its impact therethrough to the tool I5.

A combustible charge is formed within the charge forming unit I 6, comprising a gas tank and carburetor assembly, and delivered through the passage I1 to the sub-piston compression space, where it is partially compressed upon the downward stroke of the piston and then delivered through the transfer passage I8 to the combustion chamber where it is compr essed upon the return of the piston and fired at the appropriate time by initiation of a spark across the terminals of the spark plug I9. A suitable timer 20, cam actuated from the piston surface, serves to control ignition current supplied through the cable 2|. Starting of the hammer is achieved by manually forcing the starting rod 22 downwardly to depress the piston against the resistance of the return springs, and then releasing the starting rod to allow the piston to move upwardly to firing position. The general operation of hammers of this type is known to the art, and will not be fur-' ther described here.

The hammer is provided with a pair of working handles 23 and 24 extending on opposite sides of the hammer, the grip portions being spaced a substantial distance from the center thereof. These handles are mounted on a yoke member or handle ring 25 which surrounds the top portion of the hammer and is slidably splined thereto upon rail members 26 for vertical movement in a direction parallel to that of the piston. Shoulders are provided at the top and bottom of the rail members 26 so that this slidable movement of the handle ring, and thus of the handles, is limited to a relatively short distance. The handle ring has fastened thereto a throttle rod or throttle member 2'! extending downwardly therefrom substantially parallel to the cylinder and mounted for longitudinal movement in a bore 28 intersecting the passage [1. The throttle member has a portion 29 of a width substantially equal to that of the passage I1, and a'portion 30 of reduced cross-section. A spring 3! serves to normally urge this throttle member downwardly to hold the reduced portion 3B in registration with the passage I1, so that sufiicient combustible charge may pass therethrough for full'working operation of the piston.

When the hammer is in working position, resting on the tool l5, the operator exerts downward pressureon the handles 23 and 24, and these handles stay in the lowermost position of their movement, so that the member movable therewith is in what might be termed open position, with the reduced portion in registry with the passage l'l. When it is desired to move the tool to a new position, however, mere lifting of the hammer by the handles is suflicient to subdue the piston reciprocation to idling action. Lifting on the handles causes them to move relative to the hammer body or rail members 26 on which they are mounted, carrying the throttle member up with them until their further movement with respect to the hammer body is stopped by the upper shoulder on the rail members. At this point the portion 29 of the throttle member substantially closes the passage [1, as may be more readily seen from the fragmentary view in Fig. 5, so that only suflicient charge is permitted to pass therethrough to prevent the motor operation of the piston from stopping entirely. As soon as the tool I is cated at the new point on which it is desired to work and the hammer is replaced in working position, the handles move downwardly with respect to the body until they strike the lowermost shoulder on the rail members 26 whereupon the reduced portion 30 again registers with the passage l1 and a full charge ,is supplied to the cylinder to achieve the desired'working power.

The operation of the throttling mechanism is fully automatic, in that no conscious act with relation thereto is necessary by the operator. Mere lifting of the hammer by the handles throttles reciprocation of the piston to idling, and replacing of the hammer in working position at once restores it to full power operation; During such movement the operator does not have to move his hands from their working position on the grips of the handles 23 and 24, .and'the movement of the handles with relation to the hammer body is limited to such a relatively slight movement that it causes no inconvenience during lifting of the hammer.

In order to prevent automatic throttling when desired a latch member 32 is provided. This is urged inwardly by a' spring 33 to latch into a recess provided therefor in the hammer body when the handles are in their lowest position, as illustrated in Fig. 3. A pair of notches 34' and 35 are provided in the end of the handle 24, one being deeper than the other. When the upturned end of the latch member 32 lies in the deeper notch 34, the inner end engages the recess in the hammer body and latches the handles in working position, so that even when the hammer is lifted it remains at full power operation. When the upturned end is moved to lie in the notch 35, however, the automatic throttling operation is achieved.

The particular form of throttle member and connection to the handles has been found to be the best yet devised to withstand the effects of the vibration ever present in a hammer of this type. Butterfly and other rotating closures in a passage are utterly impracticable where they are exposed to the terrific impact shock occurring 1530 times or more a minute when such a hammer is working; and linkages involving jointed rods or flexible wires have been found equally unable to withstand the effects of continued vibration. In the form shown the throttle member and connection to the handle ring are all one integral rod, sliding in a bore which is vertical, so that as far as possible transverse wear between the rod and the bore is eliminated, since the main vibration axis of the hammer is vertical. While the reduced portion 30 is here shown as circular in cross-section and concentric with'the larger portion 29, it is to be understood that any desired shape of reduced portion pro viding less width blocking the passage 11 is effective.

The particular hammer illustrated in these first five figures not only incorporates the throttling feature heretofore described, but also improved and simplified 'means for rotating the tool l5 when the hammer is drilling. When the, tool is breaking a rock in order to prepare a hole for the subsequent use of a blasting medium, for example, it is necessary that it be substantially continuously rotated during hammer operation in order to prevent sticking in the hole. ,Air operated. drills generally provide positive power operated means for accomplishing this rotation, but these means are not adapted for use with a free piston hammerof the type shown here. Instead, a ratchet device located at the bottom of the hammer serves to permit unidirectional rotation only of the tool with respect to the hammer, and drill rotation is achieved by oscillating the hammer back and forth about the axis of the tool, as indicated in Fig. 2.

Referring more particularly to Figs. 3 and 4, a ratchet device is shown comprising a sleeve member 38 having an internal polygonal bore through which the tool l5 passes, the outside of the sleeve being provided with teeth adapted to interact with ratchet members 3'! and 38 on opposite sides thereof. These ratchet members comprise substantially cylindrical members lying in the bore of cylindrical housing portions 39, keyed to prevent rotation as by the key member 43. Coil springs 4! and 42, held in the bore behind the ratchet members, serve to urge them yieldingly toward the teeth on the 'rotatable sleeve 36.

In order to secure the desired rotation of the tool, the operator uses the same handles 23 and 2a with which he is supporting the hammer in working position to simultaneously oscillate the hammer about its central axis, coincident with that of the tool 55. This oscillation does not have to be throughouta very large arc. In the particular form shown here, where the sleeve member 36 has eight teeth, an oscillation of slightly more than 45 would be all that would be necessary. This would be sufficient to insure the ratchet members moving to and looking with a new tooth upon each oscillation. Where it is desired to secure rotation with a lesser movement it is only necessary, of course, to increase the number of teeth on the ratchet sleeve or to provide additional ratchet members out of registry with each other. The tool sticks in the hole sufficient to overcome the slight resistance between the parts of the ratchet, and thus upon clockwise rotation of the hammer (in the particular modification shown here) the ratchet members move to engage a new tooth, and upon counterclockwise movement of the hammer the tool is rotated in the hole being drilled. Appropriate passages in the tool and anvil assembly are provided for the introduction of fluid under pressure through a conduit 43 in order to blow out any material in the hole at desired intervals.

The method of drill rotation provided for in the hammer shown herein provides simple and effectual uni-directional rotation of the tool while drilling without the necessity for a separate power source to provide such rotation. Oscillation of the hammer is not inconvenient to the operator, since in drilling it is generally preferable to put little or no downward pressure on the handles, it being found that a series of rapid blows, even if they are not quite so heavy, secure faster progress through a rock than slower and heavier blows. This is, of course, not the case where the hammer is being used as a buster or breaker, since there it is preferable that the operator exert considerable downward pressure on the tool through the handles.

While the reciprocation of the piston was sul dued, in the modification heretofore described, by throttling or lessening the frequency and power of the reciprccations, it has been found equally advantageous to automatically stop the working reciprocation or the piston entirely when the hammer is lifted, provided that the hammer is so constructed and arranged that full working reciprocation starts again automatically when the hammer is replaced in working position. That is, there is no objection to stopping the piston if the operator does not have to remove his hands from the working handles or perform any particular operation in order to restart the hammer when it is again placed on the work. This stopping and starting is accomplished automatically when the hammer is moved from place to place during working by the structure shown in Figs. 6 and 7, which structure also may be used, where desired, for initially starting the hammer.

In this embodiment of the invention, a pair of handles (ii and 62 are carried by a yoke member 63 which is slidably mounted on the rail members M carried by the body of the hammer 55. The yoke is provided with a pair of racks 65 and 87 disposed on opposite sides of the starting rod 68, which is here toothed in its upper portion to form another pair of racks. Between each of the first mentioned racks and the starting rod is located a pinion to efiect working connection therebetween. These are here shown as pinions SS and ll! rotatably mounted on the stub shafts M and i2. Upward movement of the handles 6i and E52 with respect to the ham mer, when the hammer is lifted, causes the racks (iii and ii? to engage the pinions 8i} and iii to effect downward movement of the starting rod 68. When the hammer is replaced in working position, the starting rod is again pulled up to the position illustrated in Fig. 7, out of contact with the piston l3 and sealing the combustion chamber.

When the hammer is working and it is desired to move it to a new position, it is only necessary for the operator to lift upwardly on the working handles 6! and 62, whereupon the starting rod iiii moves downwardly to engage the piston and stop its movement. This engagement only takes place, of course, during upward movement of the piston, and consequently the only force tending to create a shock in the handles is the relatively weak return spring energy. The piston has already transferred a fresh charge, moreover, from the sub-piston space to the combustion. chamber thereabove, and thus it is held in step position but with a full charge above it. As soon as the hammer is dropped to working position at the new point, the movement of the handles causes the starting rod to return to the position shown in Fig. 7 whereupon the piston finishes its upward travel and ignites the charge at the proper interval. Full working reciprocation of the piston commences at once, without any necessity for the operator to put the hammer down and go through any particular starting operation.

In addition to temporarily stopping and then automatically restarting reciprocation of the piston when the hammer is working, this modification enables initial starting of the hammer by movement of the working handles. That is, when it is desired to start the hammer for the first time, as in the morning, it would first be primed in accordance with known operation methods to admit a very rich charge, the ignition switch would be turned on, and then the handles would be pumped up and down a. time or two with rela-.

tion to the hammer body. This would cause a charge to be drawn into the sub-piston compression space, transferred to the combustion chamber and fired to effect the desired start.

While I have described and claimed certain embodiments of my invention it is to be under stood that it is capable of many modifications. Changes, therefore, in the construction and arrangement may be made without departing from the spirit and scope of the invention as disclosed in the appended claims in which it is my intention to claim all novelty inherent in my invention as broadly as permissible in View of the prior art.

I claim:

1. A percussive hammer of the character described, including: a cylinder; a piston reciprocable therein; a tool adapted to receive impacts therefrom when said hammer is working; and means for automatically subduing the reciprocation of said piston when said hammer is lifted, said means permitting unhindered reciprocation when said hammer is returned to working position.

2. Aninternal combustion percussive hammer of the character described, including: a cylinder; a piston reciprocable therein; means for supply ing a combustible charge to said cylinder to effect reciprocation of said piston; a tool adapted to receive impacts therefrom when said hammer is working; and means for automatically subduing the reciprocation of said piston when said hammer is lifted, said means permitting unhindered reciprocation when said hammer is returned to working position.

3. An internal combustion percussive hammer of the character described, including: a cylinder; a piston reciprocable therein; means for supplying a combustible charge to said cylinder to effect reciprocation of said piston; a tool adapted to receive impacts therefrom when said hammer is working; a lifting handle mounted on said hammer but movable with respect thereto; and means actuated by movement of said handle when said hammer is lifted from working position thereby for subduing the reciprocation of said piston.

i. A hammer of the character claimed in claim 3, wherein said handle is splined to said hammer for limited movement with respect thereto.

5. An internal combustion percussive hammer of the character described, including: a cylinder; a piston reciprocable therein; means for supply ing a combustible charge to said cylinder to effect reciprocation of said piston; a tool adapted to receive impacts therefrom when said hammer is working; a pair of handles splined to said hammer for limited vertical movement with respect thereto, whereby said hammer may be lifted from working position by said handles or downward pressure may be exerted therethrough on said tool; and means actuated by upward movement of said handles when said hammer is lifted ther by for subduing the reciprocation of said piston.

6. An internal combustion percussive hammer of the character described, including: 'a cylinder; a piston reciprocable therein; means for supplying a combustible charge to said cylinder to effect reciprocation of said piston, said means including a passage; a tool adapted to receive impacts therefrom when said hammer is working; and means for partially blocking said passage to lessen the reciprocations of said piston, said means being automatically actuated when said hammer is lifted from working position. 7

'7. Apparatus of the character claimed in claim 6, wherein said blocking means is mounted for slidablc movement in said hammer.

8. An internal combustion percussive hammer of the character described, including: a cylinder; 2. piston reciprocable therein; means for supplying a combustible charge to said cylinder to effect reciprocation of said piston, said means including a passage; a tool adapted to receive impacts therefrom when said hammer is working; a lifting handle mounted on said hammer but movable With respect thereto; and means for partially blocking said passage to lessen the reciprocations of said piston, said means being actuated by movement of said handle when said hammer is lifted from working position thereby.

9. An internal combustion percussive hammer of the character described, including: a'cylinder; a piston reciprocable therein; means for supplying a combustible charge to said cylinder to effect reciprocation of said piston, said means including a passage; a tool adapted to receive impacts therefrom when said hammer is working; apair of handles splined to said hammer for limited vertical movement with respect thereto, whereby said hammer may be lifted from working position by said handles or downward pressure may be exerted therethrough on said tool; and means for partially blocking said passage to lessen the reciprocations of said piston, said means being actuated by movement of said handles when said hammer is lifted from working position thereby.

10. Apparatus of the character claimed in claim 9, wherein said blocking means comprises a longitudinally slidable member connected to said handles and having a reduced portion in said passage when said handles are in working position.

11. An internal combustion percussive hammer of the character described, including: a cylinder; a piston reciprocable therein; means for supplying a combustible charge to said cylinder to efiect reciprocation of said piston, said means including a passage; a tool adapted to receive impacts therefrom when said hammer is working; and means for partially blocking said passage to lessen the reciprocations of said piston, said means comprising a member slidably mounted for movement transverse to said passage, said member having a portion of a width substantially equal to that of said passage and a portion of reduced width, said last mentioned portion normally registering with said passage.

12. Apparatus of the character claimed in claim 11, wherein the movement of said member is substantially parallel to that of said piston.

13. An internal combustion percussive hammer of the character described, including: a cylinder; a piston reciprocable therein; means for supplying a combustible charge to said cylinder to effect reciprocation of said piston, said means in-" eluding a passage; a tool adapted to receive impacts therefrom when said hammer is working; and means for partially blocking said passage to lessen the reciprocations of said piston, said means comprising a rod member slidably mounted for movement substantially parallel to that of said piston in a bore intersecting said passage and transverse thereto, said member having a portion of a width substantially equal to that of said passage and a portion of reduced:

width normally registering with said passage, said member also extending substantially to the top of said hammer'and adapted to be actuated therefrom. a

14. An internal combustion percussive hammer of the character described, including: a cylinder; a piston freely reciprocable therein; means for supplying a combustible charge to said cylinder to effect downward movement of said piston; a

spring for effecting upward movement thereof; a-

tool adapted to receive impacts therefrom when said hammer is working; and means for automatically moving said piston to depressed position against said spring when said hammer is lifted V 15. An internal combustion percussive hammer of the character described, including: a cylinder; a piston freely reciprocable therein; means for supplying a combustible charge to said cylinder'to effect downward movement of said piston; a spring for effecting upward movement thereof; a tool adapted to receive impacts therefrom when said harrmer is working; a lifting handle mounted on said hammer but movable with respect-thereto; and means actuated by movement of said handle when said hammer is 1ifted,'for moving said piston to and retaining it in depressed position against said spring.

16. An internal combustion percussive hammer of the character described, including: a cylinder;

a piston freely reciprocable therein; means for supplying a combustible charge tosaid cylinder to effect downward movement of said piston; a spring for effecting upward movement thereof; a tool adapted to receiveimpacts therefrom when said hammer is working; a starting rod adapted to contact said piston to move it to depressed position against said spring; a handle splined to said hammer for movement in a direction parallel to that of said piston; and means connecting said handle to said rod, whereby movement of said handle when said hammer is lifted thereby effects downward movement of said piston.

17. Apparatus of the character claimed in claim 16, wherein said last mentioned means comprises a rack and pinion.

18. An internal combustion percussive hammer of the character described, including: a cylinder; a piston freely reciprocable therein; means for supplying a combustible charge to said cylinder to effect downward movement of said piston; a spring for effecting upward movement thereof; a tool adapted to receive impacts therefrom when said hammer is Working; a starting rod adapted to contact said piston to move it to depressed position against said spring; a pair of handles splined to said hammer for movement together in a direction parallel to that of said piston; and means connecting said handles to said rod whereby movement of said handles when said hammer is lifted thereby effects downward movement of said piston.

19. Apparatus of the character claimed in claim 3, wherein latch means is provided for looking said handle in working position.

20. Apparatus of the character claimed in claim 9, wherein latch means is provided for locking said handles in Working position.

21. A percussive hammer of the character de-' scribed, including: a cylinder; a piston reciprocable therein; a tool adapted to receive impacts therefrom when said hammer is working; and means movable with respect to said hammer and adapted to automatically subdue the reciprocation of said piston when moved upwardly with respect to said hammer, said means permitting unhindered reciprocation of said piston when in lowered position.

22. An internal combustion percussive hammer of the character described, including: a cylinder; a piston reciprocable therein; means for supplying a combustible charge to said cylinder to eifect downward movement of said piston; a spring for effecting upward movement thereof; a tool adapted to receive impacts therefrom when said hammer is working; a handle mounted on said hammer and movable with respect thereto; and means actuated by movement of said handle when said hammer is lifted for moving said piston to and retaining it in depressed position against the resilient force of said spring.

CARL L. CHARLES. 

